1. Field of the Invention
This invention relates to apparatus for metering and/or distributing liquid media which device comprises a manifold and a plurality of discharge conduits which depend from said manifold. This invention also relates to the use of the apparatus for supplying liquids which contain available chlorine into streams of cooling water having varying rates of flow.
2. Discussion of the Prior Art
There are numerous processes in which liquid media must be metered. It may be necessary to discharge liquid media, such as sulfuric acid, used for the drying of gases, as uniformly as possible onto the surface of packing contained in a tower, which is flown through by the gas from bottom to top, or to carry out reactions between gases and liquid media, e.g., in the production of hypochlorite from chlorine gas and sodium hydroxide solution in an operation which is similar to that described for the drying of gas. Apparatus for metering liquid media are also required, e.g., in numerous processes of treating water to which dissolved chemicals must be added, e.g., in order to precipitate or flocculate impurities or to disinfect the water.
In the processes mentioned hereinbefore it is essential that the metering be effected not only at a single point because this would necessitate a subsequent mixing, e.g., by mechanical means, and that the liquid medium is distributed as effectively as possible as it is discharged. For instance, when water is treated in a separate container, it is comparatively easy to effect a uniform distribution of the chemicals, e.g., if special feed pipes and intermediate plates are provided as well as radial partitions, which define a large number of separate chambers into which the conduits for discharging the chemicals open (German Patent Publication 18 16 526). Similar remarks are applicable to the manifold which is disclosed in Opened German Specification 26 10 387 and by which fluids are sprayed under pressure into a liquid to be treated and elastic hoses having a residual stress are fitted over the spray discharge openings and by the static pressure of the sewage are forced onto the openings in a closing sense whereas the fluid being sprayed tends to expand the hoses so as to provide a passage.
Difficulties will arise if the liquid medium is to be discharged into other flowing fluids, e.g., in the processes mentioned hereinbefore. These difficulties will be aggravated if the discharge rate of the medium is to be varied with time. That problem will arise, e.g., in processes of drying gases having a varying moisture content or in chemical processes in which the content of gaseous reactants in the gas varies. A special situation arises in the treatment of flowing water, e.g., in the chlorination of cooling water streams, for instance, with a hypochlorite solution, if the so-called continuous chlorination is to be combined with a so-called shock chlorination. In that case the chlorine discharge rate is to be increased for a short time, e.g., to two to ten times the normal rate. Because the same chlorinating agent is used, the liquid discharge rate is to be increased at the same ratio.
It is an object of the invention to provide an apparatus which is simple in structure and permits of an exact control of the metering rate and/or distribution of the liquid medium and of a change of the discharge rate in intervals of time.